Thread Links Date Links
Thread Prev Thread Next Thread Index Date Prev Date Next Date Index

Re: Long distance links


Please allow me add to your comments.

Rich Taborek wrote:

> However, there is no need for
> any 802.3 activity to define such coexistence at 10 GbE Ethernet rates. Once the 10
> GbE standard is set, many efficient implementations which route 10 GbE to SONET will
> spring up.

This is quite an interesting and appealing argument.

> Paul's proposal specifically excludes most 10 GbE PHY proposals by requiring
> specific encoding and delimiter usage to the point of requiring that the Ethernet
> PHY = SONET OC-192 PHY. I don't believe that this is in the best interest of 802.3.

I do also have some concern about the line of logics Paul has suggested.

As far as I know MII data rate with concern to SONET is one thing and the Ethernet line
coding is another.

According to my understanding of Paul' picture:

    MAC --(MII)-- 9.58Gbps --(backpressure)-- SONET Payload
            -- Add SONET overhead -- SONET Line Coding(NRZ)
            -- SONET line rate of 9.95Gbps


    MAC --(MII)-- 10.0Gbps -- 10GbE PHY w/ line coding
            -- 10GbE line rate(;depends on the line code chosen)

As I understand, we're arguing on the MII rate which sits above the PHY layer. In that
far, the decision on the line rate should not affect the choice of the 10Gbe PHY line


Dae Young